How Much Is a Car Diagnostic Test?
Ellie Dyer-Brown, 21 days ago
5 min read
- Diagnostic
- Cost
FixMyCar discusses how much you can expect to pay for a diagnostic test.
Modern cars rely on electronic monitoring systems to make sure the engine, brakes and other components are working as they should. This happens in the background until a problem is detected, at which point the driver is alerted by the appearance of a dashboard warning light.
Working out what triggered a warning light can be tricky without the help of a fault code-reading device. You could spend hours inspecting different components without getting to the bottom of the problem. That’s what a diagnostic test is for - it provides a quick and easy way to determine what’s wrong with a vehicle.
Contents
What is a car diagnostic test?
What is a car diagnostic test?
A diagnostic test uses specialist equipment to interrogate a car’s onboard computer. Basic diagnostic tools read the fault code that triggered a dashboard warning light, providing insight into the problem based on the code.
However, many garages use advanced equipment capable of providing a more sophisticated performance overview, including data on the following:
This kind of advanced test can diagnose developing and existing problems. Learn more about what a diagnostic test is and how it works.
How much is a car diagnostic?
The average price of a car diagnostic test booked through FixMyCar is £54.62.
Average price by manufacturer
| Car make | Average price |
|---|---|
| Audi | £54.42 |
| BMW | £54.23 |
| Citroen | £54.52 |
| Fiat | £53.96 |
| Ford | £54.38 |
| Kia | £56.74 |
| MINI | £55.40 |
| Mercedes | £56.35 |
| Nissan | £54.51 |
| Peugeot | £53.66 |
| SEAT | £53.13 |
| Skoda | £53.94 |
| Toyota | £53.90 |
| Vauxhall | £54.73 |
| Volkswagen | £54.98 |
Average price by model
| Model | Average price |
|---|---|
| Audi A3 | £55.28 |
| BMW 1 Series | £55.99 |
| Ford Focus | £56.10 |
| Hyundai Tucson | £53.70 |
| Kia Sportage | £59.58 |
| Nissan Juke | £55.33 |
| Nissan Qashqai | £54.31 |
| Volkswagen Golf | £54.74 |
| Volkswagen T-Roc | £56.99 |
What should I do if my check engine light appears?
The check engine light comes on in response to a variety of problems. If it’s yellow and continuous, you can keep driving for a short while as the problem isn’t urgent. You should pull over immediately if it’s red or flashing.
The first thing to do when you see the check engine light is look at your other dashboard lights and gauges for clues. Make sure your car has enough coolant and engine oil, and if it starts to overheat, you should stop driving to prevent further damage.
Most importantly, when you see your check engine light, you should take your car to a mechanic for a repair. The longer you drive with a fault, the worse it is likely to get, resulting in a higher repair bill.
Diagnostic trouble codes
Trouble codes in most modern vehicles have been standardised and are known as OBD-II (onboard diagnostics) codes. They are generated when the engine control unit (ECU) detects that a system or part isn’t working as expected and are stored in the vehicle’s memory.
OBD codes generally follow the same format, making them easier to diagnose. There are over 200 variations falling into four main categories:
Chassis codes begin with a ‘C’ and refer to most mechanical systems, including the steering, suspension and brakes.
Body codes start with a ‘B’, covering airbags, aircon, driver assistance and general passenger safety.
Codes beginning with a ‘U’ indicate problems relating to the wiring, computer, vehicle network and sensors.
Powertrain codes start with a ‘P’, signalling problems with the drivetrain, engine and transmission components.
Book a diagnostic test
Whether a warning light has appeared on your dashboard or you just want insights into your car’s performance, FixMyCar can help you find a reliable local garage for a diagnostic test.
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Written by Ellie
Ellie is FixMyCar's Content Writer. She has over three years of experience writing about cars and regularly collaborates with automotive experts to provide trustworthy advice for drivers in a language they understand. Her work has been featured in Yahoo! Finance, iNews, The Daily Express and The Sun. She has a BA in English literature and an MA in creative writing from Durham University. Outside of work, Ellie follows F1 and eagerly awaits Ferrari's next era of dominance in the sport. She drives a Suzuki Swift.
